Perhaps the most important component to any e-cigarette or vapor device is the e-liquid. No matter your setup or vaping style, every vaper needs e-liquid. You may have heard it referred to as juice, liquid, e-juice, or possibly another variation, but it all means the same thing: it's the liquid component that gets vaporized and inhaled.
E-liquid is comprised of up to 4 ingredients:
There are 3 important numbers when looking at e-liquid: the nicotine strength, the size, and the PG/VG ratio. Nicotine strength is measured in mg/mL, which is often shortened to “mg” only. You will often see nicotine strengths such as 3mg, 6mg, 12mg, etc. Sometimes, the nicotine level of the e-liquid will be measured in a percentage, and you'll see the nicotine level displayed as 0.3%, 0.6%, 1.2%, etc. An easy way to convert mg to percentage is to move the decimal place to the left by 1 digit, and change “mg” to “%.” For example, 24mg would become 2.4%. Conversely, 1.8% would be equivalent to 18mg.
Determining which nicotine strength is best for you requires some trial and error. A good place to start for most people is 6mg, but it depends on how much nicotine you're used to. If you're still craving nicotine at 6mg, try increasing it to 12mg. If it's harsh or if you don't feel well, try decreasing your nicotine strength. And of course, if you're not used to any nicotine, just use 0mg! Also, keep in mind that you'll get more nicotine from Direct-Lung vaping than from Mouth-to-Lung vaping. If switching from MTL to DL, it is strongly recommended that you decrease your nicotine strength by at least 50%.
The size of the bottle is generally displayed in milliliters (mL). The most popular sizes are 10mL, 15mL, 30mL, and 50mL, although bottles of any size can be used by the manufacturer. To provide some context, 30mL is equal to 1 ounce. Any given volume of liquid will vary in how long it lasts, based on how often someone takes a puff, what setup they're using, etc. Also, remember that the size of the bottle has no bearing on nicotine strength. Any given volume of 3mg e-liquid, for example, will always be 3mg, since it's actually 3mg/mL.
The PG/VG ratio tells you how much PG and VG are used in the base liquid.
Vapers who lung-hit generally prefer high-VG liquids. The atomizers they use are designed to feed thicker e-liquid to the coil faster, so thinner liquid tends to leak. Also, DL vapers tend to prefer more vapor production, and VG is better for that. Since each flavor extract used in e-liquid can be a different concentration or simply a stronger or weaker flavor, many liquids are designated “Max VG.” Since most flavorings use PG as a base, it's virtually impossible to create 100% VG liquids, so manufacturers simply omit PG from their base liquid, and add flavoring. As such, each flavor may have a different PG/VG ratio, so it's much easier to label these liquids as “Max VG.”
One thing to note is that e-liquid is not, and contains no, oil. Even though some people refer to e-liquid as “oil,” this is incorrect. There's a simple way of experiencing the difference. If you were to rub olive oil all over your hands and run them under water, your hands would still be oily. Water and oil separate, and water doesn't do a good job of cleaning off oil without soap. On the other hand, if you were to rub e-liquid on your hands (without nicotine, of course) and run them underwater, you'd find that your hands are clean. E-liquid is closer to an alcohol than an oil, and it mixes with water. It's important to note the difference, because some people prefer to make their own e-liquid instead of buy it, and there are certain flavorings that are oil-based. Not only will these oil-based flavorings ruin an atomizer, but they may also be related to negative health effects. To avoid confusion, it's important to refer to things as precisely as possible, and calling e-liquid “oil” is not only incorrect, but may be dangerous.
One thing that's important to recognize, especially if you're a new vaper, is that eventually, you're going to vape an e-liquid that you don't like. Even the same type of flavor between 2 different brands may taste completely different. Half the fun is sampling the thousands of different e-liquids that are out there. Most people start with tobacco flavors, but eventually move on to a variety of different flavors. Some people constantly change flavors, sometimes multiple times per day, while others find 1 liquid that they love and stick to it. The moral of the story is that there's no correct way to choose liquid. Change flavors and try new things if you want, but stick to what you know you like if that's more comfortable. Buy e-liquid if you'd like, or try your hand at making your own. This guide is a good starting point, but the world of e-liquid is endless, with discussions, reviews, and recipe sharing happening all over the internet.
Now that you know what to look for and what the numbers mean, go forth and enjoy the myriad of flavors vaping has to offer!